Found a samsung Spinpoint 1Tb here for £105.96 delivered,but its an internal. You can pick up a caddy for next to nowt though plus these drive are a really good drive, nice and quiet it maybe worth a look.
Go with Robs idea, but save another £10 here mate: http://www.ebuyer.com/product/143288
Samsung SpinPoint F1 HD103UJ 1TB Hard Drive SATAII *32MB Cache*
£96.25 delivered.
At least this way you know your getting a hard drive you really want which is realy quiet and reliable. One of the best in it's class.